INSTRUCTIONS:

Preheat oven to 375ºF.

Remove casings from sausages and crumble filling into a large oven-safe nonstick pan on medium heat; cook, stirring occasionally. After about 5 to 7 minutes, when sausage is golden brown in color and almost cooked through, add bell pepper and mushrooms. Continue to sauté until mushrooms begin to soften, about 5 minutes.

Reduce heat as low as possible (or remove from stove if using a gas range). In a medium bowl, beat egg whites with mustard, garlic powder, salt and black pepper using a whisk or handheld mixer. (Don't overdo it and make a meringue; simply incorporate flavors with eggs and lighten them up a bit.)

Distribute bread evenly over sausage-mushroom mixture, if desired. Then pour egg white mixture evenly over top. Increase heat to medium-low or medium (return pan to heat, if removed). Sprinkle cheese over top. Once egg whites start to set and turn opaque, transfer pan to oven.

Bake until cheese browns and bubbles, about 30 minutes. Remove from oven and transfer to a plate to slice and serve.